Referring to FIG. 11, a conventional blowtorch 90 includes a reservoir 91 for storing gas, a valve 92 for controlling the flow rate of the gas from the reservoir 91, a nozzle 93 for spraying the gas from the valve 92 and an igniter 94 for igniting the gas sprayed from the nozzle 93. The valve 92 includes a knob 95 operable in order to adjust the flow rate of the gas through the valve 92. The igniter 94 includes a button 96 operable so as to actuate the igniter 94 to produce a spark in order to ignite the gas sprayed from the nozzle 93. When not using the blowtorch 90, a user is required to shut down the valve 92. However, it is difficult to shut down the valve 92 completely. Leakage of the gas from the reservoir 91 is therefore inevitable. Sometimes, the user even forgets to shut down the valve 92. In both cases, the user may push the button 96 by accident, and this could incur a disaster.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.